Clamp for fastening concrete rebar intersections

ABSTRACT

A structure for clamping two rods mutually transverse to one another is described. An upwardly open seating surface has a longitudinal direction for rotationally vertically receiving a first rod in the longitudinal direction. A pair of side opening rod retainers are supported above and on opposite sides of the upwardly open longitudinal seating surface. The side openings of the retainers open in opposite directions for rotationally laterally receiving opposite sides of a second rod along a direction transverse to the longitudinal direction. The retainers include top portions spaced from the lower seating surface a distance effective to cause a rod rotationally laterally received in the side openings to exert a compressive force against a rod rotationally vertically received on the lower seating surface, thereby clamping the rods mutually transversely to each other. The clamping structure may be rotated into the intersection to vertically receive the first rod in the longitudinal seat and to laterally receive opposite sides of the second rod under the top retainer portions to press the second rod forcibly against the first rod in the longitudinal seat. Using the clamping structure in the form of a chair, a mat is formed using the chairs to transversely clamp a plurality of first and second rods at right angles, concrete is poured on the mat supported over a pour surface by the chairs, and a reinforced concrete slab is formed in which the mat is positioned at a predetermined position internally in the slab.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE DISCLOSURE

This disclosure relates to static structures which engage and support elongated reinforcing bars for embedding in a hardening material such as concrete, and in a particular to rebar support chairs and clips for crossed reinforcing bars.

FIELD OF DISCLOSURE OR TECHNICAL FIELD

Elongated reinforcing steel bars or rods (“rebar”) crossed and connected to form a horizontal grid or mat are used in the construction of poured concrete structures, such as foundation slabs, roadways, side walks, tilt up building walls and the like, to prevent the hardened concrete from separating along crack lines caused by the curing process, from load induced stress, from weather conditions, and from other causes. The rebar grid or mat holds the cracks tight, facilitates load transfer across the cracks, and restrains end movement, providing stiffness. For length, width, thickness (height) and intended use of each concrete structure, engineers determine, inter alia (i) the optimum spacing separating longitudinal bars laid out in parallel across bars laid perpendicularly to the length of the structure (cross or “transverse”) bars, (ii) the optimal spacing separating transverse bars, and (iii) the optimum height of a grid of transverse bars and longitudinal bars within a concrete form and within the formed concrete solid, all so the rebar mat functions correctly for its design purposes. In order for transverse and longitudinal reinforcing steel to effectively perform their engineered function, the rebar mat must be elevated to the design height above the pour surface before the pour, and the reinforcing steel must remain at its correct height, spacing and shape within the pour and after the pour. It is thus necessary to prevent movement of the reinforcing bars and the mat of bars during the pour.

For pours on a horizontal surface such as a roadway, the traditional method is to erect the mat in place, and then prop the mat to the design height above the pour surface. To do this, one of the lengths of rebar steel, for example the transverse rebar, is laid out on the pour surface at the specified intervals. Other lengths of rebar, in this example, longitudinal rebar, is then laid out on top of the transverse bars, and these transverse and longitudinal bars are wire tied together to form a template for the completed mat. Then the template rebar is lifted up, and supports for the template, colloquially called “chairs”, are placed under the lower bars, in the example, transverse bars, at the ends of the bars and at locations between the ends of the bars in a number sufficient to support the weight of the steel mat when it is completed, in the example, by adding remaining longitudinal rods at the design spacing and wire tying them to the transverse bars.

Plastic chairs have been developed in recent years with the goal of eliminating the need to wire tie the intersections where the chair is placed. The typical chair includes an openwardly open lower rod support for receiving a first rebar lowered into it (a “bottom bar”), and above it, at the sides of the rod support, either hook members opening in the same direction for orthogonally receiving a second rebar (a “top bar”) from one side (e.g., U.S. Pat. No. 3,673,753, Anderson), or upwardly open receivers higher than the rod support for orthogonally receiving a top bar lowered into the receivers to rest above the bottom bar. The higher upwardly open receivers generally have some means for restraining dislodgment of the top bar. Examples of the upwardly open rebar receivers include U.S. Pat. Nos. 5,893,252, 6,112,494 and 6,837,017 issued to Applicants, and U.S. Pat. Nos. 6,276,108 (Padrun), 6,557,317 (Sorkin), 6,684,595 (Sorkin), 6,962,029 (Lowrey), 7,322,158 (Sorkin), and 7,461,491 (Sorkin). These chairs position separate bottom bars and top bars in place orthogonally.

Other chairs have been described for attaching to already united crossed wires (welded wire mesh) to stand the mesh a planned distance from a pour surface: U.S. Pat. Nos. 3,378,981 (Horne) and 6,212,848 (Cooper) and International Patent Application PCT/US99/10962 (Nicol).

Cement pours are also made within upright forms to form a vertical structure, such as a barrier. A traditional method for erecting a vertical rebar mat is to cross the rebar lengths and wire tie them together at their intersections, a tedious process. Plastic clips have been described for connecting rebar. Same side opening plastic clips have been used to join rebar longitudinally (U.S. Pat. No. 4,617,775—Padrun) or at intersections: U.S. Pat. No. 3,694,988 (Skold), U.S. Pat. No. 4,110,951 (Padrun), U.S. Pat. No. 7,469,515 (Minor). Orthogonal clips have been used to join rebar: U.S. Pat. No. 5,371,991 (Bechtel et al.), U.S. Pat. No. 5,878,546 (Westover). Stirrup clips have been described for replacing wire ties for rebar runs at the corners of wire stirrups (U.S. Pat. No. 4,900,184, Cleveland).

The present invention is directed to a clamping structure for fastening separate concrete reinforcing rods together to form a clamped intersection. The invention is useful for clamping together rods crossing in adjacent horizontal planes and for clamping together bars crossing in adjacent vertical planes. The clamping structure may comprise a support (chair) or a free standing clip.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a chair clamp embodiment of this invention.

FIG. 2 is a top view of the chair of FIG. 1, showing by dashed lines bars captured mutually perpendicularly in the chair clamp.

FIG. 3. is a side view of the chair of FIG. 1 along the direction of axis Y.

FIG. 4. is a side view of the chair of FIG. 1 along the direction of axis “X”.

FIG. 5. is an isometric view of another chair embodiment of this invention.

FIG. 6. is a side view of the chair of FIG. 5 along the direction of axis “X”.

FIG. 7 is the same as FIG. 1 showing positioning of the chair below crossed bars indicating movement of the chair upwardly to engage the lower of the crossed bars.

FIG. 8 a is a top view of the chair of FIG. 1 engaged with the lower of the crossed bars ready for rotational movement to capture the bars, the arrows indicating a direction of rotation.

FIG. 8 b is a top view of the chair of FIG. 1 engaged with the lower of the crossed bars rotated in the direction of the arrows and entering engagement with the upper of the crossed bars.

FIG. 8 c is a top view of the chair of FIG. 1 showing the crossed bars of FIGS. 6 a and 6 b captured in the chair.

FIG. 9 is an isometric view of an assembly of the chair of FIG. 1 and crossed rods.

FIG. 10 is an isometric view of a mat of intersecting longitudinal reinforced rods supported and held in mutually perpendicular arrangement by chairs of the embodiment depicted in FIG. 1, embedded within a slab of concrete.

FIG. 11 Is an isometric view of a clip clamp embodiment of this invention.

FIG. 12 is a side view of the clamp of FIG. 5 along the direction of axis “X”.

FIG. 13 is an isometric view of an assembly of the clamp of FIG. 11 clamping crossed rods.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following detailed description of embodiments, reference is made to the accompanying drawings, which form a part hereof and in which are shown, by way of illustration, specific embodiments in which the invention may be practiced. Specific details disclosed herein, including what is described in the Abstract, are in every case a non-limiting description and embodiment representing concrete ways in which the concepts of the invention may be practiced. This serves to teach one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner consistent with those concepts. It will be seen that various changes and alternatives to the specific described embodiments and the details of those embodiments may be made within the scope of the invention. It will be appreciated that one or more of the elements depicted in the drawings can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Because many varying and different embodiments may be made within the scope of the inventive concepts herein described and in the specific embodiments herein detailed, it is to be understood that the details herein are to be interpreted as illustrative and not as limiting.

Reference throughout this specification to “one embodiment”, “an embodiment”, or “a specific embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of phrases such as “in one embodiment”, “in an embodiment”, or “in a specific embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

The concepts embodied in the embodiments described herein have application to any system in which rods need to be clamped together in a mutually transverse arrangement to fix the rods in a clamped intersection. The terms “rod”, “bar” and “rebar” are used interchangeably herein.

The various directions such as “upper,” “lower,” “bottom,” “top,” “back,” “front,” “transverse,” “perpendicular”, “vertical”, “horizontal,” “length,” “width, “downwardly”, “laterally” and so forth used in the detailed description of embodiments are made only for easier explanation in conjunction with the drawings. The components may be oriented differently while performing the same function and accomplishing the same result as the embodiments herein detailed embody the concepts of the invention, and such terminologies are not to be understood as limiting the concepts which the embodiments exemplify.

The term “transversely” means at a crossing angle, which is not necessarily but may be a perpendicular angle. The terms “orthogonally” or “perpendicularly” means substantially at a right angle to a reference to a degree that if not absolutely a right angle will not materially adversely affect the arrangement and function of the element described as perpendicular. The terms “vertical” or “vertically” include but are not limited to literal vertical and generally mean oriented up and down with respect to the earth's horizon to a degree that if not absolutely vertical will not materially adversely affect the function of the element described as vertical. Similarly, the terms “horizontal” or “horizontally” include but are not limited to literal horizontal and generally mean not out of level with respect to the earth's horizon to a degree that will materially adversely affect the function of the element described as horizontal. “Downwardly,” “upwardly” and “laterally” have their normal meanings; i.e., “downwardly” means: toward a lower place, point or level; “upwardly” means: toward a higher place, point or level; and “laterally” means: of, at, toward, or from the side or sides. When the term “vertically” is used in the phrase “rotationally vertically received” with regard to a rod, it is meant that where the rod is disposed in a generally horizontal plane, the rod is received by an upwardly generally horizontal movement of a structure receiving the rod or a downwardly horizontal movement of the rod with respect to the receiving structure.

As used herein, the use of the word “a” or “an” when used in conjunction with the term “comprising” (or the synonymous “having” or “including”) in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” In addition, as used herein, the phrase “connected to” means joined to or placed into communication with, either directly or through intermediate components.

Certain embodiments are disclosed for a chair structure for clamping two rods mutually transverse to one another above a pour surface. In these embodiments, the chair comprises a support; an upwardly open seating surface supported by the support and having a longitudinal direction for rotationally vertically receiving a first rod in the longitudinal direction; and a pair of side opening rod retainers each supported by the support above and on opposite sides of the upwardly open longitudinal seating surface, the side openings of the retainers opening in opposite directions for rotationally laterally receiving opposite sides of a second rod along a direction transverse to the longitudinal direction, the retainers each including a top portion spaced from the lower seating surface a distance effective to cause a second rod rotationally laterally received in the side openings to exert a compressive force against a first rod rotationally vertically received on the lower seating surface, thereby clamping the two rods mutually transversely to each other.

In an embodiment of the invention, and referring to FIGS. 1-4 and 7-9 for illustrations, a chair structure 10 for clamping two rods 100 and 200 mutually transversely to one another above a pour surface comprises a support 11, suitably comprising a base 12 and pedestal 13, and an upwardly open lower seating surface 24 supported by support 11 and having a longitudinal direction 26. The upwardly open lower seating surface may have any generally upwardly open shape, as for non-limiting example, a hollow or rod support.

In the chair, a pair of side opening rod retainers 48, 66 rise vertically from support 11 above and on opposite sides of upwardly open seating surface 24. Each side opening retainer comprises a vertical shank portion (15 in retainer 48, 19 in retainer 66) and terminates at top in an outwardly extending top portion; for shank portion 15, it is top portion 17, for shank portion 19, it is top portion 21. The term “retainer” is used without regard to configuration other than an upright shank portion and a top portion extending outwardly from the shank to cap a side opening. For non-limiting example, retainers can take the shape of an inverted “L”, a sideways “J”, a “C”, or a “G.” All these shapes are side opening and all have a vertical shank (15 in retainer 48, 19 in retainer 66) capped with an outwardly extending top portion (17 for shank portion 15, 21 for shank portion 19). In the illustrations, a side opening in the general form of a “C” (FIGS. 1-4, 7-13) or a sideways “J” (FIGS. 5-6) is depicted, namely a side opening having an bowed shape for the shank. While these are the side opening modes illustrated, the scope of the invention is not limited to the bowed shaped of the side opening.

Whether the retainers take the general shape of a sideways “J”, an inverted “L”, a “C” or a “G”, the side openings bounded by the shanks and top portions face in opposite directions for rotationally laterally receiving opposite sides of a rod 200 in them. Vertical shank portions 15 and 19 are on opposite sides of a plane extending upwardly from the members supporting the retainers (14, 16 in FIG. 1-6 and 94 a, 94 b in FIGS. 11-13). Top portions 17 and 21 extend outwardly in opposite directions in general paralleling the longitudinal direction 26. In other words, retainer 48 is open on the side of the vertical shank 15 in the direction pointed by the top portion 17 of retainer 48, and retainer 66 is open on the side of the vertical shank 19 in the direction pointed by the top portion 21 of retainer 66. Top portions 17 and 21 point in opposite directions, so the side openings of the retainers are on opposite sides of their respective shanks.

Each retainer 48 and 66 is adapted to rotationally laterally receive opposite sides of a rod 200 under their respective outwardly extending top portions 17, 21 such that, when captured inside the side openings under the top portions, the rod ends up transversely oriented to the longitudinal direction 26. Shank 15 of retainer 48 blocks lateral movement of a rod 200 rotationally received under outwardly extending top portion 17 except in the direction in which top portion 17 extends. Shank 19 of retainer 66 blocks lateral movement of a rod 200 rotationally received under outwardly extending top portions 21 except in the direction in which top portions 21 extends. Each retainer (48 or 66) is spaced from the other retainer (66 or 48) on opposite sides of the lower longitudinal seating surface 24 with the top portions 17, 21 spaced from the lower seating surface 24 a distance effective to cause a rod 200 rotationally laterally received under the top portions 17, 21 to exert a compressive force against a rod 100 rotationally vertically received on the lower seating surface 24, thereby clamping the rods mutually transversely to each other. This spacing locks the rods 100 and 200 together and restrains upper rod 200 from being displaced laterally from retainers 48, 66.

In one embodiment, the shanks 15, 19 of retainers 48, 66 each take the form of an arch about an included concavity or recess, respectively recesses 50, 68. In this configuration, the recesses 50, 68 share a common axis “X”, that is both retainers 48, 66 are centered upon and in a circumferential relationship with axis “X.” Axis “X” is transverse to the longitudinal direction 26 of the seating surface 24 and is spaced above surface 24 a distance effective to cause a rod 200 rotationally laterally received in retainers 48, 66 coaxial to axis “X” to exert a compressive force against a rod 100 rotationally vertically received on the lower seating surface 24. In the embodiments illustrated in FIGS. 1-13, axis “Y” occupies the longitudinal direction 26. Axis “X” is perpendicular to axis “Y”. An additional axis, axis “Z” (indicated by reference numeral 96) is centered on the union in the embodiments of FIGS. 1-9 where the pedestal legs 14, 16, 18, 20 described below centrally join, and in the embodiment of FIGS. 11-13, axis “Z” is centered where the cross members 91, 92 unite. Axes “X”, “Y” and “Z” are mutually perpendicular to one another.

In another embodiment, as in FIGS. 5 and 6, the retainer shanks 15, 19 each comprise a shape in the general form of an sideways “J” in which the shank 15, 19 is an arched part of the general form of the “J.” In shorthand rendition this retainer as well as a shank in which the shanks 15, 19 and top portion 17, 21 are linear in form (an inverted “L”) sometimes is referred to herein as a “finger clip”, and is described in further detail below.

In the embodiments of FIGS. 1-4, 7-9 and 11-13, additional basal structure is provided to the shank and top extension of the retainers by forming the retainer in a general “C” shape. The additional basal structure assists in retaining rod 200 in place. More particularly, in the embodiments depicted in FIGS. 1-4 and 7-9, the retainers 48, 66 each comprise a jaw structure in the general form of the letter “C”, centered on axis “X”, the retainers 48, 66 providing a basal seating surface as hereinafter described in detail for a rod 200 rotationally laterally received in the retainers, the basal seating surface of the retainers having an elevation above the lower seating surface 24 effective to cause the compressive force against a rod 100 rotationally received in the lower seating surface.

In a shorthand rendition, the general form of the retainers 48, 66 in the general shape of a “C” (for example, as depicted in FIGS. 1-4, 7-9 and 11-13) sometimes is herein called a “C-clip.” The term “C-clip” is intended also to include a “C” shape with the additional structure of an inwardly deflectable resilient member disposed at the end portion of the top or base of the opening (giving a generally inverted “G” shape or a general “G” shape, respectively) to deflect for entrance of rod 200 and spring back to press laterally against rod 200 and provide additional retention structure for holding transverse bar 200 in the retainer.

There is provided in an embodiment a chair structure for clamping two rods mutually transverse to one another in which the upwardly facing seating surface includes sides. In this embodiment, the chair comprises a longitudinal seat having a first seating surface between seat sides. The seat is oriented in a first direction for longitudinally rotationally vertically receiving and seating a first rod inside the sides. The chair includes first and second resilient retainers each comprising a recess about a common axis transverse to the first direction. The recesses have side openings oppositely facing in the first direction. The retainers are spaced apart along the mentioned axis above and to the sides of the longitudinal seat. The recesses each have a second seating surface for seating a second rod rotationally laterally received in the recess and an opposite top surface for pressing the second rod against the second seating surface. A deepest portion of the second seating surfaces of the recesses is spaced from a deepest portion of the first seating surface a distance equal to or less than the thickness of the first rod.

The foregoing aspects of an embodiment are now described in greater detail with respect to FIGS. 1-4 and 7-9, in which an intersectional rod support or chair 10 is depicted, suitably constructed of relatively resilient plastic material, for clamping two rods mutually transverse to one another (see FIG. 9) a predetermined distance above a pour surface such as a foundation or fabricated form on which the chair 10 may stand. Chair 10 comprises a base 12 and pedestal 13 comprising four legs 14, 16, 18, 20 extending vertically from base 10. Legs 14, 16, 18 and 20 are horizontally equidistantly spaced apart, i.e. each is spaced 90 degrees from the next adjacent leg. A first pair of legs 14 and 16 is horizontally spaced 180 degrees apart and a second pair of legs 18, 20 is horizontally spaced 180 degrees apart. Second pair 18, 20 extends vertically higher than first pair 14, 16. First leg 14 of pair 14, 16 supports a first segment 22 of a upwardly open longitudinal seat 24 oriented in a first direction 26. Segment 22 has a first single side 28 and an interior bottom seating surface 30 for rotationally vertically receiving and seating a first portion of a first rod 100 in first direction 26. First rod 100 is sometimes referred to herein as lower or bottom rod 100. Second leg 16 of pair 14, 16 supports a second segment 32 of seat or bottom rod support 24. Second segment 32 has a second single side 34 and an interior bottom seating surface 36 for rotationally vertically receiving a second portion of the first rod in the first direction. First and second segments 22 and 32 unite at juncture 38 where bottom surfaces 30, 36 merge, segments 22, 32 centering about a common axis “Y” running in the stated first direction 26. Seat sides 28, 34 each have a runner, respectively 40, 42, that slopes at respective chamfers 44, 46, toward sides 28, 34 of seat segments 22, 32.

Leg 18 of pedestal second pair 18, 20 supports a first resilient rod retainer 48 above and laterally adjacent runner 40 and single side 28 of first segment 22 of bottom rod support 24. Rod retainer 48 comprises lower jaw 47 and upper jaw 49. An interior side 45 of lower jaw 47 is adjacent runner 40. First rod retainer 48 includes a first recess 50 with surfaces about an axis “X” transverse to first direction 26 axis “Y.” The surfaces of the first recess 50 include a lower seating surface 52 on the topside of lower jaw 47 for seating a first portion of a second rod 200 rotationally laterally received in first recess 50 and an upper surface 54 on the underside of upper jaw 49 for pressing the first portion of second rod 200 against lower seating surface 52 of first recess 50. Second rod 200 is sometimes referred to herein as upper or top rod 200. The bottom 56 of lower seating surface 52 is a predetermined distance higher than the bottom surface 30, 36 of bottom rod support 24. That predetermined distance is a distance equal to or less than the thickness of first or lower rod 100 and will vary according to the planned application for the chair. For example, in a road construction of 6-8 inches concrete depth, the centerlines for a mat of the rods would be about 3 inches. Lower or transverse rod may be ½ inch thick (½ inch diameter if the rod is round, as in most instance of rebar rods, it is) so the low point of the mat would be 2.5 inches above the pour surface and the high point of the mat would be 3.5 inches above the pour surface. For an application such as a tilt up wall, the pour height is typically less high and smaller transverse rods are used, for example, ⅜ inch thickness.

A first ramp 58 comprising an upper part of pedestal leg 18 slopes vertically from adjacent the interior side 45 of first rod retainer 48 toward juncture 38 of longitudinal bottom rod support 24. First ramp 60 suitably has substantially the same slope as chamfer 44.

First rod retainer 48 has upper and lower projections or detents 60, 62 extending toward each other at side opening 64 (FIG. 3) of recess 50 for laterally retaining the first portion of second rod 200 within first rod retainer 48. A web 51 interconnects members 53, 55 of upper jaw 49 to provide additional structural rigidity.

Second leg 20 of second pair 18, 20 supports a second resilient rod retainer 66 spaced from first rod retainer 48 above and adjacent the runner 42 and single side 34 of the second segment 32 of bottom rod support 24 and longitudinally spaced from but opposite the single side 28 of first segment 22. Rod retainer 66 comprises lower jaw 65 and upper jaw 67. An interior side 69 of rod retainer 66 is adjacent runner 42. Second rod retainer 66 has the same configuration as first rod retainer 48, and comprises a second recess 68 with surfaces about axis “X” common to first recess 50. The surfaces of second recess 68 include a lower seating surface 70 for seating a second portion of the second or upper rod 200 rotationally laterally received in second recess 68 and an upper surface 72 for pressing the second portion of upper rod 200 against seating surface 70. The same as for first rod retainer 48, the bottom 74 of lower seating surface 70 of second recess 68 is a predetermined distance higher than the bottom surface 30, 36 of bottom rod support 24 equal to or less than the thickness of first rod 100. Similarly, second rod retainer 66 has upper and lower projections or detents 76, 78 extending toward each other at a side opening 80 of second recess 68 for laterally retaining the second portion of the second rod 200 within second rod retainer 66. A web 57 interconnects members 59, 61 of upper jaw 67 to provide additional structural rigidity.

A second ramp 82 comprising an upper part of pedestal leg 20 slopes vertically from adjacent the interior side 69 of second rod retainer 66 toward juncture 38 of longitudinal bottom rod support 24. Second ramp 82 suitably has substantially the same slope as chamfer 46.

A realization of the invention includes a methodology for clamping two rods transversely together. The method comprises (a) placing a second rod transversely against a first rod to form an intersection; (b) placing a rod support structure adjacent said intersection, the rod support structure comprising a support, an upwardly open lower seating surface supported by the support and having a longitudinal direction, the structure further having a pair of side opening rod retainers supported by the support above and on opposite sides of the upwardly open longitudinal seating surface, the side openings of the retainers opening in opposite directions for rotationally laterally receiving opposite sides of a second rod along a direction transverse to the longitudinal direction, the retainers including a top portion spaced from the lower seating surface a distance effective to cause a rod rotationally laterally received in the side opening to exert a compressive force against a rod rotationally vertically received on the lower seating surface, thereby clamping the rods mutually transversely to each other; and (c) rotating the structure into the intersection to vertically receive the first rod in the longitudinal seat and to laterally receive opposite sides of the second rod under the top retainer portions to press the second rod forcibly against the first rod in the longitudinal seat, clamping the two rods together.

This method is now more particularly described in respect to the rod support embodiments of FIGS. 1-4 and in which reference is made to FIGS. 7-9 to illustrate the method.

Referring to those figures, side openings 64, 80 of first and second recesses 50, 68 respectively of first and second retainers 48, 66 open outwardly in opposite directions to each other, recess 50 facing and opening to the “south” (arbitrarily assigning “south” to the left as FIGS. 1 and 7 are viewed) and the recess 68 facing and opening to the “north” (arbitrarily assigning “north” to the right as FIGS. 1 and 7 are viewed). First, an intersection of first and second rods 100 and 200 is created. Referring to FIG. 7, the orientation of recess side openings 64, 80 in oppositely facing retainers 48, 66 allows chair 10 to be positioned and raised under the intersection of first and second rods 100, 200, as indicated by the up-pointing arrows 84, 85 in FIG. 5. Referring to FIGS. 8 a, 8 b, and 8 c, and as indicated by FIG. 7 and FIG. 8 a, as chair 10 is raised under an intersection of rods 100 and 200, chair 10 is rotated about the “Z” axis in the direction of arrow 86 (counterclockwise) and comes into contact first with rod 100 at ramps 58 and 82 above respectively sides 45 and 69 of lower jaws 47 and 67 of retainers 48 and 66. As shown in FIG. 8 b, as chair 10 comes into contact with ramps 58, 82 and as chair 10 continues being rotated about the “Z” axis counter-clockwise in the direction indicated by arrow 86, detent 60 of first rod retainer 48 and detent 76 of second rod retainer 66 are rotated over upper rod 200 and detents 62 and 78 are rotated under rod 200, forcing upper and lower jaws 49, 47 of first rod retainer 48 apart, and similarly, forcing upper and lower jaws 67, 65 of second rod retainer 66 apart. This same rotation moves lower rod 100 down ramps 58, 82 and closer to alignment with bottom rod support 24. Further counter-clockwise rotation of chair 100 in the direction of arrow 86 presses upper rod 200 through detents 60, 62 of first rod retainer 48 and detents 76, 78 of second rod retainer 66 into recesses 50, 68 respectively onto seating surface bottoms 56, 74, while at the same time aligning lower rod 100 with bottom rod support 24 into which lower rod 100 is pressed by the force of upper rod 200 acting on it. Because the bottom seating surfaces of retainers 48, 66 are higher than the bottom surfaces 30, 36 of bottom rod support 24 only a distance equal to or less than the thickness of said lower rod 100 and because upper surfaces 54, 72 on the underside of upper jaws 49, 67 presses the first and second portions of second rod 200 against lower seating surfaces 52, 70 of first and second recesses 50, 68, rotation of chair 10 into the intersection of rods 100 and 200 forces upper rod 200 down onto lower rod 100, clamping rod 100 against its seating surfaces 30,36, top portions 17 and 21 of retainers 48, 66 holding rod 200 against lower rod 100. Detents 60, 62 and 76, 78 assist in retaining rod 200 laterally in place. An assembly of an upper rod 200, a lower rod 100 and a chair 10 is thus formed when the recesses 50, 68 of chair 10, each respectively having an side opening 64, 80 facing oppositely in a direction parallel to the Y axis, rotationally laterally receive opposite sides of second or upper rod 200.

As indicated above, another embodiment of a chair structure is depicted in FIGS. 5 and 6. The same reference numerals as used in FIGS. 1-4 and 7-9 are used in FIGS. 5 and 6 to indicate like structure. The embodiment depicted in FIGS. 5, 6 is essentially the same as the one depicted in FIGS. 1-4 and 7-9, except the basal structure forward of seating portion 56 inclusive of lower jaw 47 and detent 62 of retainer 48 and the basal structure forward of seating portion 70 inclusive of lower jaw 65 and detent 78 of retainer 66 in the embodiment of FIGS. 1-4 and 7-9 is absent. In this embodiment, each retainer 48, 66 comprises a raised shank portion 15, 19 terminating in a top portion respectively 17 and 21. Each top portion 17 or 21 extends laterally outwardly in a direction opposite from the other top portion 21 or 17 and generally parallel to direction 26. Each shank portion 15, 19 is adapted to receive a rod 200 under the outwardly extending top portions 17, 21, transverse to the longitudinal direction 26 of upwardly open lower seating surface 24 supported by support 11. Each shank 15, 19 blocks lateral movement of rod 200 rotationally laterally received under the top portions 17, 21 except in the directions of the outwardly extending respective top portions 17, 21. Each retainer 48, 66 is spaced from the other retainer 66 or 48 on opposite sides of the lower longitudinal seating surface 24 with the top portions 17, 21 spaced from the lower seating surface 24 a distance effective to cause a rod 200 rotationally laterally received under the top portions 17, 21 to exert a compressive force against a rod 100 rotationally vertically received on the lower seating surface 24, clamping the rods 100, 200 mutually transverse to each other.

Using chair 10, a method is provided for assembling a mat 300 of concrete reinforcement rods for a concrete pour, comprising (i) laying out a plurality of first or lower rods 100 spaced substantially parallel to one another in a first rod direction; (ii) laying out a plurality of second rods 200 spaced substantially parallel to one another atop the first rods in a second rod direction transverse to the first rod direction, to provide intersections 350 of first and second rods 100, 200 at predetermined intervals; (iii) placing a chair 10 under an intersection 350 of a first rod 100 and a second rod 200 such that the longitudinal bottom rod support 24 is under the first rod 100, and raising and rotating chair 10 to align first rod 100 longitudinally with said longitudinal bottom rod support 24 and at the same time rotationally laterally receive second rod 200 through the side openings 64, 80 of first and second retainers 48, 66 into recesses 50, 68 of the retainers to clamp second rod 200 down onto first rod 100 lodged in longitudinal seat 24; and repeating step (iii) for a plurality of the intersections 350.

A method of constructing a concrete slab 500 is provided using chair 10, comprising (i) conducting the operations described in the next previous paragraph to construct a mat 300 of intersecting longitudinal rods 100, 200 and lock the intersections 350 of rods 100, 200 a predetermined height above a pour surface 400 on which the slab is to be laid, using a plurality of chairs 10; and (ii) laying a pour of concrete over the mat of locked intersections of rods 100, 200.

Thus there is also provided a concrete slab 500 having a top 502 and bottom 504 and comprising between top and bottom 502, 504 a mat 300 of intersecting longitudinal reinforced bars 100, 200 the intersections 350 of which are locked a predetermined height above the surface 400 and bottom 502 of the slab 500 by a plurality of chairs 10.

The foregoing chair structures are useful where crossing rods are disposed in adjacent horizontal planes, as depicted in FIG. 10. In another embodiment of the invention, the same superstructure as used in the embodiments shown in FIGS. 1-4 and 7-9 is used without a pedestal and base and is useful for clamping rods in adjacent planes of any orientation from horizontal to vertical. This embodiment is shown in FIGS. 11, 12 and 13, FIG. 13 showing the use of the structure to clamp two rods in adjacent vertical planes transversely together. Thus, referring to FIGS. 11 and 12, and continuing use of the same reference numerals as in FIGS. 1-4 and 7-9 for identical structure, there is provided an embodiment of a structure 90 for clamping two rods mutually transversely to one another, comprising first cross members, 93 a, 93 b and second cross members, 94 a, 94 b. Cross members 93 a, 93 b extend transversely from cross section members 94 a, 94 b to end portions 95 a, 95 b from a central union 96 along a first axis “Z” in the line of union 96.

End portions 95 a, 95 b of the first cross member support a seating surface 24 crossing at juncture 38 over the union 96 along a second axis “Y” perpendicular to the first axis “Z.” Seating surface 24 has at least on side portion, in the embodiment, a side portion 28 on one side of junction 38 above the line of cross members union 96 and another side portion 34 on the other side of the junction 38. Seating surface 24 also has a basal portion 30 adjacent side portion 28 and a basal portion 36 adjacent side portion 34. Basal portions 30, 36 face away from the union (“away” is upwardly in the side views of FIGS. 11 and 12).

End portions 97 a, 97 b of second cross members 94 a, 94 b support a pair of retainers 48, 66 separated from each other on opposite sides of the seating surface 24. Retainer 48 has a shank portion 15 and a top portion 17 defining a side opening 64 under top portion 17. Retainer 66 has a shank portion 19 and a top portion 21 defining a side opening 80 under top portion 17. Side openings 64, 80 are co-aligned along a third axis (“X”) that is perpendicular to the first axis (“Z”) and second axis (“Y”). Side openings 64, 80 face opposite directions, as seen in FIGS. 11 and 12 and to best advantage in FIG. 13. Top portions 17, 21 respectively of retainers 48,66 are spaced from respective basal portions 30, 36 of the seating surface 24 by an extent effective to cause a second rod 200 received in retainer openings 64, 80 to press on a transverse first rod 100 received in the seating surface 24 upon rotation of structure 90 about the first axis (“Z”) to clamp the two transverse rods together, as seen in FIG. 13. The embodiment 90 of FIGS. 11-13 is useful in clamping together crossing rods in any orientation. Thus structure 90 can clamp rods in adjacent vertical planes as well as rods in adjacent planes other than vertical planes. FIG. 13 depicts a first rod disposed vertically, and in an adjacent vertical plane, a second rod perpendicular to the first rod.

Use of embodiment 90 comprises: (a) placing a second rod 200 transversely against a first rod 100 to form an intersection; (b) placing clamping structure 90 adjacent the intersection, clamping structure 90 comprising first cross members 93 a, 93 b and second cross members 94 a, 94 b each extending transversely to one another to end portions from a central union 96 along a first axis “Z”, the end portions 95 a, 95 b of the first cross member supporting a seating surface 24 crossing over the union 96 along a second axis “Y” perpendicular to the first axis “Z”, the seating surface 24 having a basal portion 30 facing away from the union, the end portions 97 a, 97 b of the second cross member 94 a, 94 b supporting a pair of retainers 48, 66 separated from each other on opposite sides of the seating surface 24, each retainer 48, 66 having a shank portion (15 on retainer 48, 19 on retainer 68) and top portion (17 on retainer 48, 21 on retainer 66) defining a side opening (64 on retainer 48, 80 on retainer 68) under the respective top portions, the side openings 64, 80 being co-aligned along a third axis “X” that is perpendicular to the first and second axes (“Z” and “Y” respectively), the side openings 64, 70 facing opposite directions, the top portions 17, 21 of the retainers being spaced from the basal portion 30 of the seating surface 24 only to an extent effective to cause a second rod 200 received in the retainer openings 64, 80 upon rotation of structure 90 about first axis “Z” to press normally on first rod 100 received in the seating surface 24 upon the rotation to clamp the two rods 100, 200 transversely together at an intersection of the first, second and third axes, and (c) rotating the clamping structure 90 into the intersection to vertically receive the first rod 100 in the longitudinal seat 24 and to laterally receive opposite sides of the second rod 200 under the top retainer portions 17, 21 to press the second rod 200 forcibly against the first rod 100 in the longitudinal seat 24, clamping the two rods 100, 200 together.

The above disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all modifications, enhancements, and other embodiments that fall within the true scope of the present invention, which to the maximum extent allowed by law, is to be determined by the broadest permissible interpretation of the following claims and their equivalents, unrestricted or limited by the foregoing detailed descriptions of embodiments of the invention 

1. A structure for clamping two rods transversely to one another, comprising a. first and second cross members each extending transversely to one another to end portions from a central union along a first axis, b. the end portions of the first cross member supporting a seating surface crossing over the union along a second axis perpendicular to the first axis, said seating surface having a basal portion facing away from said union, c. the end portions of the second cross member supporting a pair of retainers separated from each other on opposite sides of said seating surface, each retainer having a shank and top portion defining a side opening under the top portion, the side openings being co-aligned along a third axis that is perpendicular to said first and second axes, said side openings facing opposite directions, the top portion of the retainers being spaced from the basal portion of the seating surface only to an extent effective to cause a second rod received in said retainer openings upon rotation of said structure about said first axis to press normally on a first rod received in said seating surface upon said rotation to clamp the two rods transversely together at an intersection of said first, second and third axes.
 2. A structure for clamping two rods mutually transverse to one another, comprising: a. a support, b. an upwardly open seating surface supported by said support, having a longitudinal direction for rotationally vertically receiving a first rod in said longitudinal direction, and c. a pair of side opening rod retainers supported by said support above and on opposite sides of said upwardly open longitudinal seating surface, the side openings of said retainers opening in opposite directions for rotationally laterally receiving opposite sides of a second rod along a direction transverse to said longitudinal direction, said retainers including a top portion spaced from said lower seating surface a distance effective to cause a rod rotationally laterally received in said side opening to exert a compressive force against a rod rotationally vertically received on said lower seating surface, thereby clamping the rods mutually transversely to each other.
 3. A chair structure for clamping two rods mutually transverse to one another above a pour surface, comprising: a. a support including a base, b. an upwardly open lower seating surface supported by said support and having a longitudinal direction, and c. a pair of side opening rod retainers supported by said support above said lower longitudinal seating surface, each rod retainer comprising a raised shank portion terminating in a top portion extending outwardly in a direction opposite from the outwardly extending top portion of the other shank, each retainer being adapted to receive a rod under said outwardly extending top portions transverse to said longitudinal direction, each shank portion preventing lateral movement of a rod rotationally received under said top portions except in the outwardly extending direction of said top portions, each retainer being spaced from the other retainer on opposite sides of said lower longitudinal seating surface with said top portions spaced from said lower seating surface a distance effective to cause a rod rotationally laterally received under said top portions to exert a compressive force against a rod rotationally vertically received on said lower seating surface clamping the rods mutually transverse to each other.
 4. The chair of claim 3 in which said retainers each arch about an included recess, each recess having an axis common to the other recess, said axis being transverse to said longitudinal direction of said seating surface and spaced above said surface a distance effective to cause a rod coaxially rotationally received in said retainers to exert a compressive force against a rod rotationally vertically received on said lower seating surface.
 5. The chair structure of claim 4 in which said retainers each comprise a finger clip pointing in opposite directions.
 6. The chair structure of claim 4 in which said retainers each comprise a C-clip centered on said axis, said retainers providing a basal seating surface for a rod rotationally received in said C-clip, said basal seating surface of said C-clip having an elevation above said lower seating surface effective to cause said compressive force against a rod rotationally received in said lower searing surface.
 7. A structure for clamping two rods mutually transverse to one another, comprising: a. a longitudinal seat having a first seating surface between seat sides and oriented in a first direction for vertically rotationally receiving and seating a first rod longitudinally inside said sides, b. first and second resilient retainers each comprising a recess about a common axis transverse to said first direction, said recesses having oppositely facing side openings, said retainers being spaced apart along said axis above and to the sides of said longitudinal seat, said recesses each having a second seating surface for seating a second rod rotationally laterally received in the recess and an opposite surface for pressing the second rod against the second seating surface, a deepest portion of the second seating surfaces of the recesses being spaced from a deepest portion of said first seating surface a distance equal to or less than the thickness of said first rod.
 8. The structure of claim 7 in which the longitudinal seat has a side laterally adjacent only the side opening of each retainer.
 9. The structure of claim 8 in which said seat side has a top that slopes to the interior of the seat.
 10. The structure of claim 9 further comprising a ramp sloping from a side of each said retainer laterally adjacent said longitudinal seat to said top of said side of said longitudinal seat.
 11. The structure of claim 7 further comprising a base and a pedestal extending upwardly from said base, said pedestal supporting said longitudinal seat and said first and second retainers.
 12. The chair of claim 7 in which said retainers each include upper and lower detents extending towards each other at the side opening of the recess of the respective retainers for laterally retaining said second rod within said retainers.
 13. A chair body of relatively resilient plastic material for clamping two rods mutually transverse to one another a predetermined distance above a ground on which the chair sits, comprising: a. a base; b. four legs extending vertically from said base horizontally equidistantly spaced apart, a first pair of legs being horizontally spaced 180 degrees apart and a second pair of legs being horizontally spaced 180 degrees apart, said second pair extending vertically higher than said first pair, said first pair having: i. a first leg supporting a first segment of a vertically open longitudinal rod support oriented in a first direction and having a first single side and an interior bottom surface for receiving a first portion of a first rod in said first direction, and ii. a second leg supporting a second segment of a vertically open longitudinal rod support oriented in a first direction and having a second single side and an interior bottom surface for receiving a second portion of said first rod in said first direction, said first and second segments uniting in said bottom surface about a common axis, and said second pair having: iii. a first leg supporting a first resilient retainer above and to one side of said rod support, said first retainer comprising a first recess with surfaces about an axis transverse to said first direction, said surfaces of the first recess including a lower seating surface for seating a first portion of a second rod rotationally received in the first recess and an upper surface for pressing the first portion of the second rod against the seating surface of the first recess, with a bottom of the seating surface of the first recess supported a distance higher than said bottom surface of the rod support equal to or less than the thickness of said first rod, said first retainer having upper and lower projections extending toward each other at an side opening of the recess for laterally retaining said first portion of said second rod within said first retainer, and iv. a second leg supporting a second resilient retainer spaced from said first retainer above and to a side of said rod support opposite said one side, said second retainer comprising a second recess with surfaces about a common axis to said first recess, said surfaces of said second recess including a lower seating surface for seating a second portion of said second rod rotationally received in the second recess and an upper surface for pressing the second portion of the second rod against the seating surface of the second recess, with a bottom of the seating surface of the second recess supported said distance higher than said bottom surface of the rod support, said second retainer having upper and lower projections extending toward each other at an side opening of the second recess for laterally retaining said second portion of said second rod within said second retainer,  said side openings of said first and second recesses oppositely facing in said first direction for rotationally laterally receiving opposite sides of said second rod and grippingly transversely clamping said second rod down onto said first rod, and c. wherein said single sides of said first and second segments of said longitudinal seat are respectively adjacent the side openings of the first and second retainers, wherein each such seat side has a top that slopes to the interior of the seat, and wherein a ramp slopes from a side of each said retainer adjacent said longitudinal seat to said top of said single side of said longitudinal seat adjacent said side opening of said retainer.
 14. An assembly comprising: a. a base, b. an upwardly open lower seating surface supported by said base and having a longitudinal direction, c. a first longitudinal rod rotationally received in said longitudinal direction on said lower seating surface, d. a pair of rod retainers supported by said base above said lower longitudinal seating surface, each rod retainer comprising a raised retainer terminating in a portion extending outwardly in a direction aligned in said longitudinal direction and opposite the direction of the outwardly extending portion of the other retainer, e. a second rod rotationally received transverse to said longitudinal direction under said outwardly extending portions, each retainer preventing lateral movement of said rod rotationally received under said portions except in the outwardly extending direction of said portion, each retainer being spaced from the other retainer on opposite sides of said lower longitudinal seating surface with said portions spaced from said lower seating surface a distance effective to cause said second rod to exert a compressive force against said first rod rotationally received on said lower seating surface, clamping the rods mutually transverse to each other.
 15. A method of clamping two rods mutually transverse to one another, comprising: a. placing a second rod transversely against a first rod to form an intersection, b. placing a structure adjacent said intersection, said structure comprising a support, an upwardly open lower seating surface supported by said support and having a longitudinal direction, and a pair of side opening rod retainers supported by said support above and on opposite sides of said upwardly open longitudinal seating surface, the side openings of said retainers opening in opposite directions for rotationally laterally receiving opposite sides of a second rod along a direction transverse to said longitudinal direction, said retainers including a top portion spaced from said lower seating surface a distance effective to cause a rod rotationally laterally received in said side opening to exert a compressive force against a rod rotationally vertically received on said lower seating surface, thereby clamping the rods mutually transversely to each other; c. rotating said structure into said intersection to vertically receive said first rod in said longitudinal seat and to laterally receive opposite sides of said second rod under said top retainer portions to press said second rod forcibly against said first rod in said longitudinal seat.
 16. A method of assembling a mat of longitudinal rods for a concrete pour, comprising: a. providing a plurality of intersectional rod supports each comprising i. a base, ii. an upwardly open lower seating surface supported by said base and having a longitudinal direction, and iii. a pair of rod retainers supported by said base above said lower longitudinal seating surface, each rod retainer comprising a raised retainer terminating in a portion extending outwardly in a direction opposite from the outwardly extending portion of the other retainer, each retainer being adapted to receive a rod under said outwardly extending portions transverse to said longitudinal direction, each retainer preventing lateral movement of a rod rotationally received under said portions except in the outwardly extending direction of said portion, each retainer being spaced from the other retainer on opposite sides of said lower longitudinal seating surface with said portions spaced from said lower seating surface a distance effective to cause a rod rotationally received under said portions to exert a compressive force against a rod rotationally received on said lower seating surface clamping the rods mutually transverse to each other. b. laying out a plurality of first rods spaced substantially parallel to one another in a first rod direction; c. laying out a plurality of second rods spaced substantially parallel to one another atop said first rods in a second rod direction transverse to the first rod direction to provide intersections of first and second rods at predetermined intervals; d. placing a said rod support under an intersection of a said first rod and a second rod such that said upwardly open longitudinally directed lower seating surface is under the first rod, and rotating said rod support to align the first rod longitudinally with said longitudinally directed lower seating surface and receive the second rod under said oppositely extending portions of said retainers to clamp said second rod down onto said first rod lodged in said longitudinal lower seating surface; and e. repeating step (d) for a plurality of said intersections.
 17. A method of constructing a concrete slab comprising: a. constructing a mat of intersecting longitudinal reinforced rods, b. locking the intersections of the rods a predetermined height above a surface on which the slab is to be laid, using a plurality of intersectional rod supports each comprising i. a base, ii. a pedestal extending upwardly from said base, iii. an upwardly open longitudinal rod support supported by said pedestal, oriented in a first direction and having sides and an interior bottom surface for longitudinally receiving a first rod in said first direction, iv. first and second resilient retainers respectively comprising interior recesses with surfaces about a common axis transverse to said first direction, said surfaces of each recess including a lower seating surface for seating a second rod rotationally received in the recess and an upper surface for pressing the second rod against the seating surface of the recess, said retainers being supported by said pedestal spaced apart from one another above and to the sides of said rod support with a bottom of the seating surface of each of the recesses supported higher than said bottom surface of the rod support a distance equal to or less than the thickness of said first rod, said recesses each having an side opening oppositely facing in said first direction for rotationally laterally receiving opposite sides of said second rod and grippingly transversely clamping said second rod down onto said first rod.
 18. A concrete slab having a top and bottom and comprising between the top and bottom a mat of intersecting longitudinal reinforced rods the intersections of which are locked a predetermined height above the bottom of the slab by a plurality of intersectional rod supports each comprising: a. a base, b. a pedestal extending upwardly from said base, c. an upwardly open longitudinal rod support supported by said pedestal, oriented in a first direction and having sides and an interior bottom surface for longitudinally receiving a first rod in said first direction, d. first and second resilient retainers respectively comprising interior recesses with surfaces about a common axis transverse to said first direction, said surfaces of each recess including a lower seating surface for seating a second rod rotationally received in the recess and an upper surface for pressing the second rod against the seating surface of the recess, said retainers being supported by said pedestal spaced apart from one another above and to the sides of said rod support with a bottom of the seating surface of each of the recesses supported higher than said bottom surface of the rod support a distance equal to or less than the thickness of said first rod, said recesses each having an side opening oppositely facing in said first direction for rotationally laterally receiving opposite sides of said second rod and grippingly transversely clamping said second rod down onto said first rod. 